Unless the cable is pure silver, which it isn't, there's not much to attribute anything less bright to other than cable config and alloy/plating technique. It's obviously changed and likely for the better but the more silver part is marketing. OCC is just as good as silver in use. The rest is tonal matching. As silver oxidizes/corodes, that portion actually becomes nonconductive and the resistance differences are neglegable in this use and easily adjusted if it were. Nothing against silver but it's not the big deal many think it is. Perhaps it can better but it it wont be untill alot of more important things are better first. Silver plated or rolled copper tends to be worse than a good OCC for instance. Correlation does not mean causation though I'm sure that a better more expensive cable with more silver content is used. Going away from silver after having it would not be good marketing.

All that said, I'm happy that Vsonic isn't ignoring an issue and have taken steps to improve it. I'm sure they have or they wouldn't have called attention to it.

Is the cable less stiff? Is it finally possible to wear them without earhooks? :)

I wore my pair of the old GR07s (NOT MKII's) without ear hooks as i had them on loan to review and it was hard work. They do not like to stay per you ear so for that respect i gues you will want the ear hooks when you wear them

Can anyone explain electrically how adding more silver to a cable can help with sibilance?

Here's my humble guess:

sibilance is caused by unevenness/spikes in the treble. Since silver is more conductive, it would allow the treble signals to move more freely (I read somewhere that treble is the fastest to get to the driver), evening out the freq response a bit up top.

Take that with a grain of salt because I'm more versed in chemistry and biology than I am physics.

They may have improved the design of the bio-cellulose driver in the lab process, or it's geometry, or reduced the internal resonance of the IEM, and are simply saying "more silver in the cable reduced sibilance" since that's easier. ;)

Swimsonny noted there's already been several revisions of the GR07 prior to the MK2, three I think? The changes are unclear but they seem pretty dedicated to good sound, my R04 updated version doesn't have many faults in it as an IEM.

They may have improved the design of the bio-cellulose driver in the lab process, or it's geometry, or reduced the internal resonance of the IEM, and are simply saying "more silver in the cable reduced sibilance" since that's easier. ;)

Swimsonny noted there's already been several revisions of the GR07 prior to the MK2, three I think? The changes are unclear but they seem pretty dedicated to good sound, my R04 updated version doesn't have many faults in it as an IEM.

AFAIK the only revision to the GR07 was when they updated the accessory package. Some reported increased warmth. It's never been confirmed though.

I've listened to the Vsonic GR07 very quickly on two occasions, the first time they sounded quite similar to the Hifiman RE252, and quite different to the Sony EX600 (they're in the same sentence so often I expected they would be similar, the soundspace is notably different for one).

The second time they sounded more refined and interesting, however this was half a year or so apart, and the second unit had 400 hours of burn-in or something, if that exists. =]

sibilance is caused by unevenness/spikes in the treble. Since silver is more conductive, it would allow the treble signals to move more freely (I read somewhere that treble is the fastest to get to the driver), evening out the freq response a bit up top.

Take that with a grain of salt because I'm more versed in chemistry and biology than I am physics.

Spikes are essentially dB peaks in the frequency response.....where drivers are more responsive to the voltage applied at this frequency. Silver is more conductive but this effects the entire frequency range AFAIK. The only way it could reduce sibilance (assuming nothing else has changed) is if silver attenuates higher frequencies but I just don't see this.

On open box there was sibilance, they were very edgey in their presentation, border line harsh. I had to drop my EQ treble to compensate. it wasn't terrible but present none the less especially at higher volumes .Sibilance would appear when ever I turned volume up easily, never though at any point did I think I can't live with this, it was bareable. As I was burning in it started easing off, they become smoother each listen (about 15 hours each interval)

Not much changed for the first 50 hours but for piece of mind my EQ settings were still saved in VLC media player from open box. I had to start lifting the treble a touch to compensate each interval, that to me is a sure sign something was going on. Now they're at a point I can't notice it anymore and I'm having to find it in tracks I know are renowned for it to test. Also testing between MKII and my TF10 - TF10 are now showing sibilance in tracks the MKII are not. This has so far been my experience and I'm taking them up to 200 of the 300 hours recommended.